A polyrotaxane is expected to be useful in various applications because of its viscoelasticity, and thus various materials comprising the polyrotaxane have been developed (see, for example, Patent Document 1).
On the other hand, especially in the care welfare field, there are strong needs for an operation support device which can be used easily, and which is light, with a rapid advance of an aged society. The conventional operation support device used an electromagnetic motor for the drive system, and thus had the fault that it was difficult to save the weight of the support device. For this reason, development of the actuator excellent in lightweight nature, a response, durability, and safety is desired. Although various types of the actuator have been proposed, the dielectric actuator using a polymer has been especially expected, in order to solve the above problems (see, for example, Patent Document 2).